Plants inspire self-assembling, self-healing photovoltaic technology

MIT researchers design a super cell that can convert light into energy more efficiently than conventional solar cells.
Written by Boonsri Dickinson, Contributing Editor

Plants produce energy by consuming carbon dioxide and tapping sunlight to produce glucose. The plants do this for years on end, thanks to their super efficient repair mechanism.

For instance, a leaf on a tree can recycle its protein every 45 minutes. Solar panels aren't that lucky. Most solar cells are damaged when exposed to constant sunlight.

To make more efficient solar panels, researchers are interested in mimicking what happens inside chloroplasts.

While commonly used silicon-based photovoltaic cells don't show signs of degradation, new types of solar cells can show signs within 60 hours (even causing the efficiency to decrease to 10 percent of the original conversion rate). Now, that's a serious difference!

"We're basically imitating tricks that nature has discovered over millions of years" — in particular, "reversibility, the ability to break apart and reassemble," MIT's chemical engineer Michael Strano said in a statement.

The photocell is built with several parts, which include:

  • carbon nanotubes
  • phospholipids (form discs)
  • proteins (part of the reaction center)

Nanotubes hold the discs in place, which expose the phospholipids to the light. When the conditions are ripe, the parts assemble themselves, so they can produce an electric current.

To be sure the system could self-assemble, the researchers added a surfactant (which is like the chemical BP added to the oil) to the system, the researchers said. The seven parts disassembled and turned into a soupy mess. When the researchers washed the soup off, the parts re-assembled.

The new system is about 40 percent efficient, compared to conventional cells that are only 20 percent efficient. The researchers are hopeful they can up the efficiency of their self-assembling cell to 100 percent.

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